Micro-CT evaluation of morphological degenerative features of sterno-clavicular joint for age-at-death estimation in forensic anthropology - A qualitative analysis.

The analysis of the sternoclavicular joint holds significant importance in forensic anthropology, especially through the evaluation of medial clavicular ossification stage, which, however, is helpful only in subjects younger than 30 years of age. Given this limitation, the aim of the present work was to examine, through micro-CT, the surface of sternoclavicular joints of deceased individuals across various age groups, aiming to identify age-related degenerative changes applicable to age estimation in adults over 30 years old. A total of 41 deceased subjects were categorized into three age groups (20-39 years; 40-59 years; ≥60 years) for the analysis. Degenerative morphological features on both clavicular and sternal articular surfaces, including topography, porosity, and presence of osteophytes, were evaluated using a composite scoring system based on a modified "Falys-Prangle method.", which assigns to each parameter specific score ranges: 1-3 for surface topography (smooth, slightly irregular, markedly irregular), 1-6 for porosity (absent, micro- and macroporosity for <50 % or >50 % of surface, surface breakdown), 1-3 for osteophytes (absent, present, not evaluable). The findings revealed a positive correlation between degenerative morphological features and age for both clavicular (rs = 0.719) and sternal articular surfaces (rs = 0.750). Additionally, the combined assessment of the clavicle and sternum, or the evaluation of the clavicle alone, exhibited better differentiation among the three age groups. The micro-CT evaluation of degenerative alterations affecting the sternoclavicular joint proves to be a reliable and efficient method for age estimation in adults.

Prevalence and morphometry of sternal and xiphoid foramen: a meta-analysis on 16,666 subjects.

PURPOSE: Sternal foramen is a perforation of the sternum that can be a source of misdiagnosis during radiographic imaging or life-threatening perforations during bone marrow sampling. The aim of this study was to conduct a meta-analysis on the prevalence, morphometrics, and location of foramen in the sternal body and xiphoid process, describe morphometric features of this phenomenon, and thus verify its clinical importance. Moreover, our secondary outcome was to compare effectiveness of various imaging methods in diagnosis of the sternal or xiphoid foramen. METHODS: A comprehensive search was conducted on major scientific databases to identify studies containing relevant information. Data on foramen's prevalence, location, morphometrics, and accompanying findings were extracted and pooled into a meta-analysis using MetaXL 5.0. RESULTS: Thirty-five studies (n = 16,666 subjects) were included. The overall pooled prevalence of a foramen in the sternal body and/or a xiphoid process was 8.9% (95% CI 6.5-11.7) and it equaled 6.5% (95% CI 5.6-7.6) for sternal body alone and 2.9% (95% CI 0.5-6.9) for the xiphoid process. The foramen was more prevalent in males than in females (12.2% vs. 6.8%). The prevalence of sternal foramen was higher in South American [13.9% (95% CI 11.2-16.9)] and African [13.6% (95% CI 9.7-18.0)] studies compared to North American [6.2% (95% CI 5.0-7.5)] and European populations [8.6% (95% CI 3.1-16.3)]. Mean transverse and vertical diameter of foramen equaled 4.7 mm (95% CI 3.8-5.5), and 5.6 mm (95% CI 4.2-6.9), respectively. CONCLUSION: Our analysis proves that the sternal foramina are structures of significant prevalence and size. Any physician should keep them in mind when performing punctures in this area.

Sexing the sternal rib end in modern Greeks: A virtual osteometric approach using high-resolution 3D surface models.

Sex determination is one of the first biological attribute to be assessed when unidentified remains surface. In material of forensic interest, being able to use every skeletal element available for identification purposes is of paramount importance. The osteometric method from the sternal rib end has been found to generate accurate sex estimates, but as various studies have proved, all osteometric methods should be population-specific, as one equation does not fit all. The aim of this study is to assess sexual dimorphism in a contemporary Greek population sample of 68 males and 43 females, with the use of discriminant function analysis. The superior-inferior height (SIH) and anterior-posterior breadth (APB) from the third to fifth sternal rib ends of both sides were taken from 3D models created with the use of a hand-held 3D scanner. The results demonstrated that SIH is more sexually dimorphic than APB (alpha value of .05) while the application of Iscan's (1985) formula on the contemporary Greek sample, provided results of low accuracy, ranging from 48.6-52.4%. The cross-validated discriminant functions equations for the current sample, produced results ranging between 74.0-82.9% indicating that population-specific formulas produce results of higher accuracy, that are vital in cases of forensic interest.

Preserved soft anatomy confirms shoulder-powered upstroke of early theropod flyers, reveals enhanced early pygostylian upstroke, and explains early sternum loss.

Anatomy of the first flying feathered dinosaurs, modern birds and crocodylians, proposes an ancestral flight system divided between shoulder and chest muscles, before the upstroke muscles migrated beneath the body. This ancestral flight system featured the dorsally positioned deltoids and supracoracoideus controlling the upstroke and the chest-bound pectoralis controlling the downstroke. Preserved soft anatomy is needed to contextualize the origin of the modern flight system, but this has remained elusive. Here we reveal the soft anatomy of the earliest theropod flyers preserved as residual skin chemistry covering the body and delimiting its margins. These data provide preserved soft anatomy that independently validate the ancestral theropod flight system. The heavily constructed shoulder and more weakly constructed chest in the early pygostylian Confuciusornis indicated by a preserved body profile, proposes the first upstroke-enhanced flight stroke. Slender ventral body profiles in the early-diverging birds Archaeopteryx and Anchiornis suggest habitual use of the pectoralis could not maintain the sternum through bone functional adaptations. Increased wing-assisted terrestrial locomotion potentially accelerated sternum loss through higher breathing requirements. Lower expected downstroke requirements in the early thermal soarer Sapeornis could have driven sternum loss through bone functional adaption, possibly encouraged by the higher breathing demands of a Confuciusornis-like upstroke. Both factors are supported by a slender ventral body profile. These data validate the ancestral shoulder/chest flight system and provide insights into novel upstroke-enhanced flight strokes and early sternum loss, filling important gaps in our understanding of the appearance of modern flight.

The earliest segmental sternum in a Permian synapsid and its implications for the evolution of mammalian locomotion and ventilation.

The sternum is a stabilizing element in the axial skeleton of most tetrapods, closely linked with the function of the pectoral girdle of the appendicular skeleton. Modern mammals have a distinctive sternum characterized by multiple ossified segments, the origins of which are poorly understood. Although the evolution of the pectoral girdle has been extensively studied in early members of the mammalian total group (Synapsida), only limited data exist for the sternum. Ancestrally, synapsids exhibit a single sternal element and previously the earliest report of a segmental sternum in non-mammalian synapsids was in the Middle Triassic cynodont Diademodon tetragonus. Here, we describe the well-preserved sternum of a gorgonopsian, a group of sabre-toothed synapsids from the Permian. It represents an ossified, multipartite element resembling the mammalian condition. This discovery pulls back the origin of the distinctive "mammalian" sternum to the base of Theriodontia, significantly extending the temporal range of this morphology. Through a review of sternal morphology across Synapsida, we reconstruct the evolutionary history of this structure. Furthermore, we explore its role in the evolution of mammalian posture, gait, and ventilation through progressive regionalization of the postcranium as well as the posteriorization of musculature associated with mammalian breathing.

The Intersection Between the Sternocleidomastoid and Splenius Capitis as the Anatomical Landmark to Facilitate Occipital Artery Harvest: A Retrospective Clinical Study.

BACKGROUND: Occipital artery (OA)-posterior inferior cerebellar artery (PICA) bypass is a challenging procedure and is not frequently performed owing to the difficulty of OA harvest. To facilitate harvest, the intersection between the sternocleidomastoid and splenius capitis (the OA triangle) is used as the anatomical landmark to identify the OA segment that carries the highest risk of damage. This clinical study aimed to demonstrate efficacy and safety of OA harvest using this landmark. METHODS: The study included 18 patients who underwent OA harvest using the OA triangle as a landmark for treatment of vertebral artery and PICA aneurysms. Patients were retrospectively evaluated for safety and patency of OA after harvest and OA-PICA bypass. RESULTS: Of 18 patients with ruptured and unruptured vertebral artery and PICA aneurysms, 13 (72.2%) underwent OA-PICA bypass and 5 (27.8%) did not undergo bypass. The OA was completely harvested without damage in all patients. After harvest, the OA was patent in 17 patients (94.4%) and was occluded in 1 patient owing to vasospasm; this patient then underwent recanalization resulting in good patency of the OA-PICA bypass. The patency rate of the OA-PICA bypass was 100%. CONCLUSIONS: The OA triangle, which is the anatomical landmark of the proximal end of the transitional segment of the OA, facilitated OA harvest using the distal-to-proximal harvest technique with safety and good patency. To the best of our knowledge, this is the first study of OA harvest in clinical cases.

Estimation of sex based on metrics of the sternum in a contemporary Jordanian population: A computed tomographic study.

ABSTRACT: There is a paucity of osteometric standards for sex estimation from unknown skeletal remains in Jordan and the sexual dimorphism of the sternum has not yet been investigated. The aim of this study was to evaluate the sexual dimorphism in sternal measurements using 3D multidetector computed tomography (MDCT), and to assess their reliability for sex estimation in a Jordanian population. A total of 600 MDCT scans (300 males and 300 females) were used and a total of 8 sternal measurements were studied (manubrium length, sternal body length, combined length of manubrium and body, corpus sterni width at 1st and 3rd sternebrae, sternal index and area). Sexual dimorphism was evaluated by means of discriminant function analyses. Significant sexual dimorphism was found mainly in middle-aged and older adults. Including all subjects, multivariate, and stepwise functions gave an overall accuracy of 83.0% and 84.0%, respectively. Additionally, multivariate and stepwise analyses were conducted separately for each age group. The accuracy of sex estimation in multivariate analysis (all variables) varied from 63.2% in the young, and 83.7% in the middle adults to 84.9% for older adults. In stepwise analysis, the highest accuracy rates were provided by only sternal area in young adults (81.6%), and sternal area combined with sternal body length in middle-aged and older adults (84.2% and 85.3%, respectively). The best sex discriminator using univariate analysis (single variable) was sternal area followed by sternal body length (84.0% and 80.8% respectively). Notably, univariate analyses for most variables gave relatively higher classification accuracies in females but were poor at predicting males in the sample (sex bias ranged between -6.4% and -20%). Our data suggest that dimorphism in the human sternum increases with advancing age and separate discriminant functions are needed for each age group in Jordanians. In addition, multivariate and stepwise analyses using sternum gave higher classification accuracies with comparatively lower sex biases compared to univariate analyses.

The relationship between sternum variation and mode of locomotion in birds.

BACKGROUND: The origin of powered avian flight was a locomotor innovation that expanded the ecological potential of maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). The avian sternum is the anchor for the major flight muscles and, despite varying widely in morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal variation across a broad phylogenetic scope of birds using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches to test hypotheses of sternum size allometry and the correlation of sternal shape with both size and locomotory capabilities, including flightlessness and the highly varying flight and swimming styles of Neornithes. RESULTS: We find evidence for isometry of sternal size relative to body mass and document significant allometry of sternal shape alongside important correlations with locomotory capability, reflecting the effects of both body shape and musculoskeletal variation. Among these, we show that a large sternum with a deep or cranially projected sternal keel is necessary for powered flight in modern birds, that deeper sternal keels are correlated with slower but stronger flight, robust caudal sternal borders are associated with faster flapping styles, and that narrower sterna are associated with running abilities. Correlations between shape and locomotion are significant but show weak explanatory power, indicating that although sternal shape is broadly associated with locomotory ecology, other unexplored factors are also important. CONCLUSIONS: These results display the ecological importance of the avian sternum for flight and locomotion by providing a novel understanding of sternum form and function in Neornithes. Our study lays the groundwork for estimating the locomotory abilities of paravian dinosaurs, the ancestors to Neornithes, by highlighting the importance of this critical element for avian flight, and will be useful for future work on the origin of flight along the dinosaur-bird lineage.

Age estimation from sternebral fusion in an Indian population - A computed tomographic evaluation.

Forensic age estimation is a crucial aspect of the human identification process. Sternebral fusion is one of the skeletal indicators of age that has not been thoroughly researched for the purpose of age estimation. The present study was conducted with the aim of assessing the utility of each of the sternebral fusion in age estimation, and to ascertain if these fusion stages can help in identifying whether an individual has attained the medicolegally significant ages of 16 and 18 years. Thoracic CT images of 148 study participants (74 females, 74 males) were analysed to evaluate the fusion of sternebrae 1-2, sternebrae 2-3, and sternebrae 3-4. The fusion scores for these were found to be statistically significant (P < 0.001) with sternebrae 1-2 fusion showing the highest coefficient of correlation at R = 0.900. Linear regression models were generated using each of the sternebral fusions separately and together for estimation of age. The standard error of estimate for the regression models ranged from 1.51 to 2.86 years. Box and Whisker plots were constructed to see the fusion score wise age distribution of the study population, and it was observed that sternebral fusion has the ability to indicate whether an individual has attained the age of 16 and 18 years. Our study concludes that sternebral fusion can act as an accurate method of forensic age estimation of juveniles and young adults.

Estimation of sex based on the sterna of Sudanese adults using multidetector computed tomography: a comparison of discriminant function analysis and binary logistic regression.

Sex estimation is critical during forensic and anthropological investigations, and various techniques are used based on the presence of complete or fragmented human remains. This study evaluated sexual dimorphism in Sudanese sterna using multidetector computed tomography. This information was used to develop models for estimating sex, and to compare the accuracies of models based on discriminant function analysis (DFA) and binary logistic regression (BLR). The study included 126 Sudanese men and 144 Sudanese women who underwent computed tomography scans to create three-dimensional reconstructions. Six linear dimensions were measured on the manubrium and mesosternum. Men had larger mean values for most parameters, and nine parameters exhibited highly significant sexual dimorphism. The leave-one-out cross-validated sex estimation accuracies were 60.4-88.9% for DFA-based models and 60.4-89.3% for BLR-based models. The BLR-based models had noticeably better performances, with six parameters having sex estimation accuracies of >80% (vs. three parameters for DFA). The best BLR-based models incorporated the lengths and widths of the manubrium and mesosternum (accuracy: 89.3%, sex bias: 2.2%) and the combined manubrium and mesosternum lengths (accuracy: 85.6%, sex bias: 2.7%). Thus, computed tomography may be useful for measuring sternal dimensions and estimating sex among Sudanese subjects.

Nationwide stature estimation from length of sternum measurements in Montenegrin adolescents / Estimación de la estatura a nivel nacional a partir de la longitud de las mediciones del esternón en adolescentes montenegrinos

SUMMARY: The purpose of this research is to determine a regression equation for estimation of stature from length of sternum measurements. This research was carried out on 1001 subjects (504 male and 497 female) among the population of Montenegrin adolescents. The stature and length of sternum measurements were taken according to the ISAK protocol, and the data were analyzed statistically. Linear regression analysis determined the prediction of and length of sternum on the criterion variable a body height at the significance level of p <0.05. These relations are presented in the form of scatter diagram. Thereby, we obtained the coefficient of determination, the multiple correlation coefficients, the partial correlation coefficient, the regression, t-test and standardized beta coefficient. The results of this research study confirmed that length of sternum reliably predicts stature in both sexes of Montenegrin adolescents and revealed a very useful finding for physical anthropologists and experts from related fields. It was confirmed that there is a correlation between length of sternum and body height (males: 33.1 %, females: 31.3 %). Therefore, length of sternum has proven to be a reliable predictor on the basis of which the actual body height can be estimated.

RESUMEN: El propósito de este estudio fue determinar una ecuación de regresión para la estimación de la estatura a partir de la longitud del esternón. El análisis se llevó a cabo en 1001 sujetos (504 hombres y 497 mujeres) entre la población de adolescentes montenegrinos. Se tomaron medidas de la estatura y la longitud del esternón de acuerdo con el protocolo ISAK, y los datos se analizaron estadísticamente. El análisis de regresión lineal determinó la predicción y la longitud del esternón en la variable de criterio de la altura del cuerpo con nivel de significancia de p <0,05. Las relaciones se presentan en forma de diagrama de dispersión. De este modo, obtuvimos el coeficiente de determinación, los coeficientes de correlación múltiple, el coeficiente de correlación parcial, la regresión, la prueba t y el coeficiente beta estandarizado. Los resultados de este estudio confirmaron que la longitud del esternón logra predecir la estatura en ambos sexos de adolescents montenegrinos de manera confiable, y reveló un hallazgo útil para los antropólogos físicos y los expertos de áreas relacionadas. Se confirmó que existe una correlación entre la longitud del esternón y la altura del cuerpo (hombres: 33,1 %, mujeres: 31,3 %). Por lo tanto, la longitud del esternón ha demostrado ser un predictor confiable sobre la base de la cual se puede estimar la altura real del cuerpo.

Hand placement during chest compressions in parturients: a pilot study to identify the location of the left ventricle using transthoracic echocardiography.

BACKGROUND: Current guidelines for maternal cardiopulmonary resuscitation recommend the hands be placed on the lower half of the sternum for compressions. We sought to evaluate the effect of the gravid uterus and left uterine displacement on the position of the left ventricle (LV) using transthoracic echocardiography. METHODS: We enrolled 20 women in the third trimester of a singleton pregnancy. Transthoracic echocardiography images in the supine and left lateral position, using a 30° wedge, were acquired. Parasternal long and short axis views of the LV were obtained at the lower half of the sternum and at the ideal imaging window (best image of mid-LV at 90° transducer orientation) The primary aim was to evaluate the distance between the distal end of the xiphoid and the location of the best imaging window of the LV. RESULTS: The cohort included women without prior anatomical cardiac disease. The LV was best visualized 5.8 (±2) cm cranial to the distal end of the xiphoid in the supine position and 6.1 (±2) cm in the lateral position (P=0.6), using the left parasternal border as a reference. No lateral cardiac displacement was evidenced in either position. CONCLUSIONS: This pilot study used transthoracic echocardiography to document the position of the LV during the third trimester of pregnancy. The LV was located approximately 6 cm cranial to the distal tip of the xiphoid process. Further validation is required before recommending changes in hand placement during maternal cardiopulmonary resuscitation.

Optimum chest compression point might be located rightwards to the maximum diameter of the right ventricle: A preliminary, retrospective observational study.

BACKGROUND: Some researchers have reported that applying compression closer to the maximum diameter of the left ventricle (Point_max.LV) is associated with worse clinical outcomes, challenging its traditional position as optimum compression point (Point_optimum). By locating the mid-sternum (the actual compression site) in terms of Point_max.LV and its right ventricular equivalent (Point_max.RV), we aimed to determine its optimum horizontal position associated with increased chances of return of spontaneous circulation (ROSC). METHODS: A retrospective, cross-sectional study was performed at a university hospital from 2014 to 2019 on non-traumatic out-of-hospital cardiac arrest (OHCA) victims who underwent chest computed tomography. On absolute x-axis, we designated the x-coordinate of the mid-sternum (x_mid-sternum) as 0 and leftward direction as positive. Re-defining the x-coordinate of Point_max.RV and Point_max.LV as 0 and 1 interventricular unit (IVU), respectively, we could convert x_mid-sternum to "-x_max.RV/(x_max.LV - x_max.RV) (IVU)." Using multiple logistic regression analysis, we investigated whether this converted x_mid-sternum was associated with clinical outcomes, adjusting core elements of the Utstein template. RESULTS: Among 887 non-traumatic OHCA victims, 124 [64.4 ± 16.7 years, 43 women (34.7%)] were enrolled. Of these, 80 (64.5%) exhibited ROSC. X_mid-sternum ranging from -1.71 to 0.58 (-0.36 ± 0.38) IVU was categorised into quintiles: <-0.60, -0.60 to -0.37, -0.37 to -0.22, -0.22 to -0.07 and ≥-0.07 (reference) IVU. The first quintile was positively associated with ROSC (odds ratio [95% confidence interval], 9.43 [1.44, 63.3]). CONCLUSION: Point_optimum might be located far rightwards to Point_max.RV, challenging the traditional assumption identifying Point_optimum as Point_max.LV.

New methods for sex estimation using sternum and rib morphology.

Sex estimation of skeletal remains is of great importance in the fields of physical and forensic anthropology. Since skeletons are often incomplete, it is essential to estimate sex from as many skeletal remains as possible. The aim of this study was to establish new methods for estimating sex using the morphology of the sternum and the fifth to ninth ribs. We considered two conditions of skeletal preservation: All skeletal elements measured are available, or only a single element is available. Traditional or virtual measurements were carried out on three samples: (1) A skeletal sample from the Hamann-Todd Human osteological collection, Cleveland Museum of Natural History, USA (N = 413), was used to create prediction equations for sex estimation. (2) A recent, CT-based sample from Israel (N = 33) was used to cross-validate the accuracy of the prediction equations. (3) A skeletal sample from the Anthropological Collection at Tel Aviv University (N = 15) was used to test the validity of the virtual measurements. Reliability and validity analyses were carried out via intraclass correlation coefficient analysis. Prediction equations for sex were created using logistic regression. The measurements were found to be highly reliable and valid. Success rates for sex estimation were high (> 80%) and correspond well between the skeletal and recent samples, especially for the left sixth, left eigth, and left ninth ribs. To conclude, measurements of the sternum and ribs are valuable for estimating sex and can be carried out using either traditional or virtual tools. Of all the skeletal elements examined in this study, the sternum, left sixth, left eighth, and left ninth ribs were found to be the most reliable skeletal elements for estimating the sex of an individual.

Applicability of Anatomical Landmarks for Chest Compression Depth in Cardiopulmonary Resuscitation for Children.

We evaluated the applicability of the neck and sternal notch (SN) as anatomical landmarks for paediatric chest compression (CC) depth using chest computed tomography. The external anteroposterior diameter (EAPD) of the neck and chest at the SN level, mid-point between two landmarks (mid-landmark), and EAPD of the chest at the lower half of the sternum (EDLH) were measured. To estimate the depths of the landmarks from a virtual point at the same height as the position for CC, we calculated the differences between the EAPDs of the neck, SN, mid-landmark, and EDLH. We analysed the relationship between the depths of the landmarks and one-third EDLH using Bland-Altman plots. In all, 506 paediatric patients aged 1-9 years were enrolled. The depths of the neck, SN, and mid-landmark were 53.7 ± 10.0, 37.8 ± 8.5, and 45.8 ± 9.0 mm, respectively. The mean one-third EDLH was 46.8 ± 7.0 mm. The means of the differences between the depths of the neck and one-third EDLH, depths of the SN and one-third EDLH, and depths of the mid-landmark and one-third EDLH were 9.0, -6.9, and 1.0 mm, respectively. The SN and neck are inappropriate landmarks to guide compression depth in paediatric CPR.

Correlation between Sternal Slope Angle and Primary Spontaneous Pneumothorax in Young Males, a Propensity Score Match Analysis.

It is generally accepted that primary spontaneous pneumothorax (PSP) is found mostly in tall, thin young males. However, the precise etiology of PSP is unclear. We compared some thoracic structural angles of PSPs and controls in young males to determine the predominant factor. CT data of 43 male PSPs (age 21.88 ± 5.30) and 30 controls (age 21.47 ± 5.47) were collected. The angle of thoracic vertebrae slope (∠α), sternal slope angle (∠ß), and tracheal-sternal stem angle (∠γ) were measured in the sagittal position. Carina angle (∠δ) was measured in the coronal position. After a propensity score match (PSM) of age and smoking history, the angles were comparatively evaluated. There were significant differences in all four angles between two unmatched groups, while only in three (∠ß, ∠γ, and ∠δ) after PSM was performed. The correlation between âˆ ß and PSP was most significant, and R2 was 0.456. The prediction accuracy of âˆ ß was 81.3%, OR was 1.386, 95% confidence interval was (1.095-1.754). The sternal slope angles in PSPs are greater than controls indicate the sternal slope angle is associates with the development of PSP and it could be a thoracic structural index to predict the risk of PSP occurrence. Clin. Anat. 33:605-609, 2020. © 2019 Wiley Periodicals, Inc.

Incidence of sternalis muscle in the Caldas population (Colombia): anatomical variations / Incidencia del músculo esternal en la población de Caldas (Colombia): variaciones anatómicas

The musculus sternalis is an anatomical variant that occurs in 3-8 % of the world population and its incidence is higher in women. It can be found unilaterally or bilaterally and is located in the anterior wall of the thorax, where its fibers run parallel to the sternum and superficial to the medial part of the pectoralis major muscle. The main objective of this study was to quantify the incidence of musculus sternalis in the population of Caldas (Colombia) and, therefore, 68 cadavers of adult individuals were used during a period of twenty years to determine the incidence of this muscle and describe its anatomical characteristics. Two cadavers had this muscle, which was equivalent to 2.94 % of the sample, where one was located unilaterally and in other bilaterally. In the case of unilateral presence, the muscle presented an oblique direction thatdoes not coincide with any subtype of the classification given for these muscles. In bilateral presentation, both muscles were continuous at their upper ends with the respective sternocleidomastoid muscle. In addition, the right musculus sternalis had a digastric shape, which also does not coincide with any subtype of the classification.

El músculo esternal es una variante anatómica que se presenta entre el 3 % y 8 % de la población mundial y su incidencia es mayor en mujeres. Puede hallarse de manera unilateral o bilateral y se localiza en la pared anterior del tórax, donde sus fibras corren paralelas al esternón y superficial a la región medial del músculo pectoral mayor. El objetivo del presente estudio fue cuantificar la incidencia del músculo esternal en la población de Caldas (Colombia). Fueron revisados 68 cadáveres de individuos adultos durante un lapso de doce años, con el fin de determinar el grado de presencialidad del músculo y sus características anatómicas. Dos cadáveres, que equivale al 2,94 % de la muestra, presentaron el músculo esternal, uno de manera unilateral y el otro bilateral, a los cuales se les hizo una descripción anatómica detallada. En la presentación unilateral, el músculo presentó una dirección oblicua que no coincide con ningún subtipo de la clasificación dada para estos músculos. En la presentación bilateral, ambos músculos se continúan por su extremo superior con el respectivo músculo esternocleidomastoideo. Además, el músculo esternal derecho tiene una configuración digástrica, que tampoco coincide con ningún subtipo de la clasificación.

Evaluation of sternum closure methods by means of a nonlinear finite element analysis.

The main purpose of this study is to develop a validated three-dimensional finite element model of sternum closure techniques. For this aim, the finite element method analysis results of three closure methods were compared with experimental test results. Also, three more closure techniques are simulated numerically to study the effect of the number of wires used in the manubrium and xiphoid regions. A three-dimensional model of polyurethane sternum foam was created based on computed tomography images. Six different closure techniques using steel wire, steel bands and ZipFix bands were modeled on the sternum and transferred into a three-dimensional finite element model. The sternum was modeled as an isotropic bilinear-elasto-plastic material, and nonlinear contact conditions were applied. The models were analyzed under lateral distraction loading, and load-displacement curves were obtained from displacements at the incision line. Allowable loads and stiffness values of the methods were evaluated from these curves. The results showed the importance of the including material as well as geometric nonlinearities in the simulations to obtain realistic results from the numerical analyses. Also, the analyses showed that closures that include steel or ZipFix bands are superior to conventional wiring, and addition of a single wire at the manubrium and xiphoid regions significantly improved the efficiency of the closure techniques.

[Anatomical relations in innominate artery compression syndrome: retrospective case-control study]. / Relaciones anatómicas en el síndrome de compresión traqueal por la arteria innominada: estudio de casos y controles retrospectivo.

OBJECTIVE: To compare the anatomical relations between brachiocephalic trunk (BT), trachea, spine and sternum in patients with Innominate Artery Compressing Syndrome (IACS) and control patients. METHODS: Retrospective case-control study of patients diagnosed with IACS in our center, in whom vascular computerized tomography (CT) was performed. The CT were compared with those of control patients free of obstructive respiratory pathology, without congenital heart disease and free of deforming thoracic mass, in whom CT was performed due to other reason. Each case was paired with three controls per case, in similar age groups. The significance value was set as p<0,05. RESULTS: Nine cases were included (7 boys and 2 girls) with their 27 respective controls (20 boys and 7 girls). The BT origin position with respect to the trachea, thought as a clock face, was 01:30 (00:30- 03:00) in cases and 01:30 (00:30-02:30) in controls. No differences were observed (p=0.72). The relation between anteroposterior/transversal tracheal diameters was 0.44 (0.184-0.6) in cases, 0.885 (0.64-1.16) in controls. The sternum-trachea/sternum-vertebra relation was 0.685 (0.6-0.76) in cases, 0.67 (0.49-0.79) in controls. No differences were observed (p=0.75). The angle of thoracic kyphosis was 29º (9º-34º) in cases, 24º (4º-33º) in controls. There were no statistically significant differences (p=0.45). CONCLUSIONS: We found no differences between the two groups in the BT origin in relation to the trachea. In all cases, the origin was on the left side of the body. Therefore, we question the premise that IACS is due to a more left origin of BT.

OBJETIVO: Analizar las distintas relaciones anatómicas entre el tronco braquiocefálico (TB), la tráquea, la columna vertebral y el esternón en pacientes diagnosticados de síndrome de compresión de la arteria innominada (SCAI) y compararlas con las de los pacientes controles. METODOS: Estudio retrospectivo de casos y controles de los pacientes diagnosticados de SCAI en nuestro centro, a los que se realizó una tomografía computarizada con contraste (TC) y/o resonancia magnética (RM). Se compararon con pacientes controles, elegidos entre enfermos sin malformación cardiaca ni masa torácica deformante, y a los que se les había realizado una TC vascular torácico por distintos problemas respiratorios no obstructivos. Por cada caso, se seleccionaron tres controles, agrupándolos por grupos de edades. Se estableció pp<0,05 como valor de significancia estadística. RESULTADOS: Se incluyeron 9 casos (7 niños y 2 niñas) y 27 controles (20 niños y 7 niñas). Se estudió en cortes transversales de la TC la posición horaria del nacimiento del TB respecto a la tráquea, resultando en los casos una posición mediana correspondiente a las 01:30 (00:30- 03:00) y en los controles a las 01:30 (00:30-02:30), sin hallarse diferencias significativas (p= 0,72). Se midió el ratio entre el diámetro anteroposterior/diámetro transverso de la tráquea, este fue de 0,44 (0,184-0,6) en los casos y 0,885 (0,64-1,16) en los controles (p=0,00001). El ratio de la distancia esternón-tráquea/esternón-columna fue 0,685 (0,6-0,76) en los casos y 0,67 (0,49-0,79) en los controles (p=0,75). El ángulo de la cifosis torácica fue 29º (9-34) en los casos y 24º (4-33) en los controles (p=0,45). CONCLUSIONES: No observamos la existencia de diferencias en el nacimiento del TB en pacientes con SCAI respecto a la población general. El TB nace en todos los niños en el lado izquierdo del cuerpo, poniendo en duda que el SCAI sea debido a un nacimiento más izquierdo del TB.

Validation of age and height based formulae to predict paediatric airway distances - a prospective observational study.

Background: Preoperative airway evaluation in children is an important part of routine preanesthetic evaluation before surgery. External airway measurements, viz., thyromental, mentohyoid, and sternomental distances, while being growth dependent, could identify pediatric patients with potentially difficult airways. Objectives: This study was conducted to validate the age- and height-based formulae, derived from a previous study conducted in our institute, to predict thyromental distance, sternomental distance, and mentohyoid distance in relation with the height and age of pediatric patients. Design: Prospective cross-sectional single arm observational study. Setting: Tertiary level university teaching hospital from July 2015 to December 2016. Patients: Children (202) in the age group of 3-15 years with no obvious external airway anomaly scheduled for elective surgery under general anesthesia. Outcomes Measured: The thyromental, mentohyoid, and sternomental distances were measured preoperatively. The same parameters were then calculated based on age- and height-related formulae derived in the earlier study. Results: Bland-Altman analysis of the sample patients showed a mean difference (bias) between measured and calculated values ranging from 0.14 to -0.60 (3 - 13%). Overall agreement in terms of bias were found to be more with height-based equation for mentohyoid distance and thyromental distance and age-based equation for sternomental distance. Conclusion: Our study validates the formulae derived in the earlier study to predict thyromental, mentohyoid, and sternomental distances in children with no obvious external airway anomalies. Further studies are needed to extend the applicability of these formulae in obese children and those with craniofacial anomalies coming for general anesthesia and surgery.